1971 Merc 500 thunderbolt, How do i adjust the mixture on the carbys ?

[CDT]

I finally got my boat into the water, It ran great for a good 10-15 mins then when we switched it off out in the water for roughly 10minutes went to restart and it wouldnt start had to choke the engine to get it to run, then when it does run you can rev it up in neutral and its fine but as soon as when you go to put it in gear it stalls (fades out) Which has led me to believe the mixture settings are wrong on the carbys

But how do i adjust them ? i have no workshop manual or anything

Thanks

 

[merc850]

Re: 1971 Merc 500 thunderbolt, How do i adjust the mixture on the carbys ?

The motor idle stop should be adjusted so that it idles about 500-600rpm in gear, just off neutral.
Start with the low speed screws at 1-1/2 turns out from seated,
warm up motor then with motor in gear and turning about 1100 rpm turn the top screw in slowly until motor starts to run badly then turn it out until it smooths out. Repeat for the bottom carb.